JP2014083504A - Photocatalyst component and method for manufacturing the same - Google Patents

Abstract

A photocatalytic functional material having high photocatalytic activity and excellent durability using hydrothermal treatment is provided.
A method for producing a photocatalytic member includes a step of hydrothermally treating a photocatalytic material such as glass or glass ceramic. The treatment temperature in the hydrothermal treatment step is preferably in the range of 100 to 450 ° C., and the treatment time is preferably in the range of 1 to 720 hours. The hydrothermal treatment is performed in at least one solvent selected from the group consisting of water, an aqueous alkaline solution, and an acidic aqueous solution. The obtained photocatalyst member is equipped with glass or glass ceramics containing a crystal phase having photocatalytic activity, and protruding inorganic crystals are deposited on the surface.
[Selection] Figure 1

Description

  The present invention relates to a photocatalytic member having excellent photocatalytic activity and a method for producing the same.

  Metal oxides such as titanium oxide and tungsten oxide are known to have photocatalytic activity. These compounds having photocatalytic activity (hereinafter sometimes simply referred to as “photocatalyst”) generate electrons and holes when irradiated with light having energy higher than the band gap energy. In the vicinity of the surface, the redox reaction is strongly promoted and decomposition of organic substances and the like occurs.

As a method for supporting a photocatalyst on a base material, many conventional techniques employ the concept of supporting a photocatalyst by forming a film containing the photocatalyst on the surface of the base material. However, a problem common to techniques based on such a concept is that it is difficult to ensure the adhesion between the substrate and the film containing the photocatalyst and the durability of the film itself. That is, in the photocatalytic functional product manufactured by these methods, the film containing the photocatalyst may be peeled off from the base material, or the film may deteriorate and the photocatalytic function may be impaired. Thus, as a technique for including a photocatalyst in a substrate, Patent Document 1 proposes glass ceramics in which a glassy composition contains crystals having photocatalytic activity such as TiO ₂ .

  By the way, hydrothermal treatment is known as a compound synthesis method or crystal growth method performed in the presence of high-temperature and high-pressure hot water, and is widely used industrially. For example, Patent Document 2 proposes a method for hydrothermal synthesis of artificial zeolite using waste soda-lime glass and water as raw materials. Patent Document 3 proposes a method of producing a zeolite by hydrothermal synthesis from an alkali-free glass in contact with an alkali solution to form a hydrogel.

JP 2009-263179 A JP 2010-111561 A JP 2012-116743 A

  An object of the present invention is to provide a method for producing a photocatalytic functional material having high photocatalytic activity and excellent durability using hydrothermal treatment.

  The manufacturing method of the photocatalyst member of the present invention includes a step of hydrothermally treating the photocatalytic material.

  In the method for producing a photocatalytic member of the present invention, it is preferable that a treatment temperature in the hydrothermal treatment step is in a range of 100 to 450 ° C.

  In the method for producing a photocatalyst member of the present invention, it is preferable that the treatment time of the hydrothermal treatment step be in the range of 1 to 720 hours.

  In the method for producing a photocatalyst member of the present invention, the hydrothermal treatment is preferably performed in at least one solvent selected from the group consisting of water, an alkaline aqueous solution, and an acidic aqueous solution.

  In the method for producing a photocatalytic member of the present invention, the photocatalytic material is preferably glass or glass ceramics.

  In the method for producing a photocatalytic member of the present invention, the glass preferably has a composition capable of precipitating crystals having photocatalytic activity by heat treatment.

  In the method for producing a photocatalytic member of the present invention, it is preferable that the glass ceramic has crystals having photocatalytic activity.

In the method for producing a photocatalytic member of the present invention, the glass or glass ceramic is in mol% with respect to the total amount of the oxide-converted composition,
(1) At least one selected from the group consisting of P ₂ O ₅ component, B ₂ O ₃ component, SiO ₂ component, and GeO ₂ component is in the range of 1 to 90%;
(2) Rn ₂ O component (where Rn means one or more selected from Li, Na, K), RO component (where R is one or more selected from Mg, Ca, Sr, Ba) Cu ₂ O component, Ag ₂ O component, ZnO component, Al ₂ O ₃ component, Fe ₂ O ₃ component, TiO ₂ component, SnO component, ZrO ₂ component, HfO ₂ component, V ₂ O ₅ component 1 or more components selected from Nb ₂ O ₅ component, Ta ₂ O ₅ component, MoO ₃ component and WO ₃ component in the range of 0.0001 to 99%;
It is preferable to contain each.

In the method for producing a photocatalytic member of the present invention, the crystal having photocatalytic activity is a NASICON crystal, TiO ₂ crystal, WO ₃ crystal, RnNbO ₃ crystal, RnTaO ₃ crystal (where Rn is Li, Na, and K). One or more selected), RNb ₂ O ₆ crystal, RTa ₂ O ₆ crystal (where R represents one or more selected from Be, Mg, Ca, Sr, Ba and Zn), ZnO crystal And one or more kinds of crystals selected from these solid solutions.

In the method for producing a photocatalyst member of the present invention, the NASICON crystal has a general formula A _m E ₂ (XO ₄ ) ₃ (wherein A is Li, Na, K, Cu, Ag, Mg, Ca, Sr, Ba, And E means at least one selected from the group consisting of Zn, Al, Fe, Ti, Sn, Zr, Ge, Hf, V, Nb and Ta. X means one or more selected from the group consisting of Si, P, S, Mo and W, and the coefficient m is 0 or more and 5 or less, and A and E are different components. It is preferable that it is represented.

  In the method for producing a photocatalytic member of the present invention, the glass or glass ceramic is preferably in the form of a powder or a plate.

  In the method for producing a photocatalytic member of the present invention, the glass or glass ceramic is preferably a porous body.

  The photocatalyst member of the present invention is a photocatalyst member provided with glass or glass ceramics containing a crystal phase having photocatalytic activity, characterized in that protruding inorganic crystals are deposited on the surface.

  In the photocatalytic member of the present invention, the inorganic crystal preferably has an average crystal diameter measured by a scanning electron microscope in a range of 0.05 μm or more and 500 μm or less.

  In the photocatalyst member of the present invention, it is preferable that the inorganic crystal is precipitated by subjecting glass or glass ceramic as a raw material to hydrothermal treatment.

In the photocatalytic member of the present invention, the crystal having photocatalytic activity is a NASICON crystal, TiO ₂ crystal, WO ₃ crystal, RnNbO ₃ crystal, or RnTaO ₃ crystal (where Rn is selected from Li, Na, and K). One or more), RNb ₂ O ₆ crystal, RTa ₂ O ₆ crystal (where R represents one or more selected from Be, Mg, Ca, Sr, Ba and Zn), ZnO crystal, and these One or more kinds of crystals selected from the solid solution of

In the photocatalytic member of the present invention, the NASICON crystal has a general formula A _m E ₂ (XO ₄ ) ₃ (where A is Li, Na, K, Cu, Ag, Mg, Ca, Sr, Ba, and Zn). E means one or more selected from the group consisting of Zn, Al, Fe, Ti, Sn, Zr, Ge, Hf, V, Nb and Ta. , X means one or more selected from the group consisting of Si, P, S, Mo and W, and the coefficient m is 0 or more and 5 or less, and A and E are different components. It may be done.

  The method for producing a photocatalytic member of the present invention can produce a photocatalytic member having high photocatalytic activity from a photocatalytic material by a simple process by utilizing hydrothermal treatment. Therefore, according to the method of the present invention, a photocatalytic member having excellent photocatalytic activity and useful as a photocatalytic functional material can be easily produced on an industrial scale without using special equipment. Moreover, the photocatalyst member obtained by the method of the present invention has a high degree of freedom in processing the size and shape, and can be used for various applications that require a photocatalytic function.

It is drawing which shows the image which image | photographed the surface of the photocatalyst member obtained in Example 1 with the scanning electron microscope (SEM). It is drawing which shows the image which image | photographed the surface of the photocatalyst member obtained in Example 2 with the scanning electron microscope (SEM). It is drawing which shows the image which image | photographed the surface of the photocatalyst member obtained in Example 3 with the scanning electron microscope (SEM). It is drawing which shows the image which image | photographed the surface of the photocatalyst member obtained in Example 7 with the scanning electron microscope (SEM). 2 is a drawing showing the results of methylene blue decomposition ability evaluation in Test Example 1. 4 is a drawing showing the results of methylene blue decomposition ability evaluation in Test Example 2. It is drawing which shows the result of Cs adsorption power evaluation in Test Example 3. FIG. It is drawing which shows the result of Cs adsorption power evaluation in Test Example 3. FIG. It is drawing which shows the result of Cs adsorption power evaluation in Test Example 3. FIG. It is drawing which shows the result of Cs adsorption power evaluation in Test Example 3. FIG. It is drawing which shows the result of the acetaldehyde decomposition ability evaluation in Test Example 4.

  The manufacturing method of the photocatalyst member of this Embodiment includes the process of hydrothermally processing a photocatalyst material.

[Photocatalytic material]
In the method for producing a photocatalytic member of the present embodiment, the “photocatalytic material” means a material having photocatalytic activity, a material that exhibits photocatalytic activity by hydrothermal treatment, or a material that enhances photocatalytic activity. As photocatalytic materials, for example, semiconductor materials such as titanium dioxide (TiO ₂ ), zinc oxide (ZnO), tungsten oxide (WO ₃ ), and semiconductor materials are doped with various components to improve response light characteristics and performance. And materials such as metal ions, metal complexes, and the like, as well as materials composed of particles, bulks, gels / liquids, and films. The photocatalytic material includes glass having a composition capable of precipitating crystals having photocatalytic activity by heat treatment, glass ceramics having crystals having photocatalytic activity, and the like. In addition, the photocatalytic material includes crystals having photocatalytic activity (photocatalytic crystals) themselves.

[Glass and glass ceramics]
The components of glass and glass ceramics as the photocatalytic material will be described. Here, the glass ceramic is a material obtained by precipitating a crystal phase in a glass phase by heat-treating glass, and is also called crystallized glass. Glass ceramics may include not only a material composed of a glass phase and a crystal phase, but also a material in which the glass phase is entirely changed to a crystal phase, that is, a material having a crystal content (crystallinity) of 100% by mass in the material. Glass ceramics can control the crystal particle diameter, the type of crystal precipitated, and the degree of crystallinity by controlling the crystallization process. In addition, in this specification, unless there is particular notice, content of each component which comprises glass and glass-ceramics shall be displayed by mol% with respect to the total amount of substances of an oxide conversion composition. Here, the “oxide conversion composition” means that the oxide, composite salt, metal fluoride, etc. used as a raw material of the glass component are all decomposed and changed into oxides when melted, and the generated oxidation It is the composition which described each component contained in glass by making the total amount of substances of a thing into 100 mol%.

The TiO ₂ component crystallizes the glass, so that Ti ions are precipitated from the glass as TiO ₂ crystals or solid solutions thereof and / or NASICON type crystals, and can impart photocatalytic activity to the glass ceramics. As the crystal form of TiO ₂ , anatase type, rutile type and brookite type are known, but anatase type and rutile type are preferable, and anatase type TiO having particularly high photocatalytic activity. It is advantageous to contain _two crystals. Further, when the TiO ₂ component is contained in combination with the P ₂ O ₅ component, it becomes possible to precipitate the TiO ₂ crystal at a lower heat treatment temperature, and the photocatalytic activity is increased from the anatase TiO ₂ crystal having a high photocatalytic activity. The phase transition to a low rutile type can be reduced. However, if the content of the TiO ₂ component is less than 20%, it becomes difficult to precipitate TiO ₂ , NASICON type crystals and their solid solution crystals, and sufficient photocatalytic activity cannot be obtained. It becomes very difficult. Therefore, when trying to precipitate TiO ₂ , NASICON type crystals and these solid solution crystals, the lower limit of the content of the TiO ₂ component with respect to the total amount of glass or glass ceramics in terms of oxide composition is preferably 20%, More preferably, it is 30%, most preferably 40%, and the upper limit is preferably 99%, more preferably 95%, most preferably 90%. However, in the case where the WO ₃ crystal or ZnO crystal described later is to be precipitated, the TiO ₂ component may not be included, but the stability and chemical durability of the glass, the improvement of the photocatalytic effect, and these crystals It is desirable to add it from the viewpoint of promoting the production of. The upper limit of the amount added is preferably 40%, more preferably 30%, and most preferably 20%. Incidentally, TiO ₂ component can be introduced into the glass or the glass ceramics used as the starting material for example TiO ₂ or the like.

The WO ₃ component is a component constituting a NASICON crystal while enhancing the meltability and stability of the glass, and can impart photocatalytic activity that responds to visible light when precipitated as a crystalline phase from the glass by heat treatment. . However, if the content of the WO ₃ component is less than 20%, it becomes difficult to precipitate WO ₃ crystals, and sufficient photocatalytic activity cannot be obtained. If it exceeds 99%, vitrification becomes very difficult. Therefore, when WO ₃ crystals are to be precipitated, the lower limit of the content of the WO ₃ component with respect to the total amount of glass or glass ceramics in the oxide conversion composition is preferably 20%, more preferably 25%, and most preferably. Is 30%, and the upper limit is preferably 99%, more preferably 95%, and most preferably 90%. However, when trying to precipitate TiO ₂ crystal, NASICON type crystal, ZnO crystal, etc., it does not need to contain WO ₃ component, but it is added from the viewpoint of improving glass stability and improving photocatalytic effect. Is desirable. The upper limit of the amount added is preferably 30%, more preferably 25%, and most preferably 20%. Incidentally, WO ₃ components can be introduced into the glass or the glass ceramics used as the starting material for example WO ₃ and the like.

The ZnO component improves the meltability and stability of the glass and constitutes a NASICON crystal. When the ZnO component is precipitated as a crystal phase from the glass by heat treatment, it can impart photocatalytic activity that responds to visible light. . However, if the content of the ZnO component is less than 20%, it becomes difficult to precipitate ZnO crystals and sufficient photocatalytic activity cannot be obtained, and if it exceeds 99%, vitrification becomes very difficult. Therefore, when ZnO crystals are to be precipitated, the lower limit of the content of the ZnO component with respect to the total amount of glass or glass ceramics in oxide equivalent composition is preferably 20%, more preferably 30%, most preferably 40. %, And the upper limit is preferably 99%, more preferably 95%, and most preferably 80%. However, in the case where TiO ₂ crystal, NASICON crystal, WO ₃ crystal or the like is to be precipitated, the ZnO component may not be included. However, from the viewpoint of improving glass stability and photocatalytic effect, 0.1% It is desirable to add at least%. The upper limit of the amount added is preferably 30%, more preferably 25%, and most preferably 20%. Incidentally, ZnO component, material as for example ZnO, the ZnF _2, etc. can be introduced into a glass or glass-ceramics using.

The P ₂ O ₅ component is a component that constitutes a network structure of glass and enhances the stability of the glass, and P ⁵⁺ ions form a NASICON crystal structure, and contributes to improvement of photocatalytic activity. It is a component that can be added. By using phosphate glass in which the P ₂ O ₅ component is the main component of the network structure, more components such as TiO ₂ , WO ₃ and ZnO can be incorporated into the glass. In addition, by blending the P ₂ O ₅ component, it is possible to precipitate TiO ₂ crystals, NASICON type crystals, WO ₃ , ZnO crystals and the like at a lower heat treatment temperature, and anatase type TiO ₂ with high photocatalytic activity. The effect of reducing the phase transition from a crystal to a rutile type having low photocatalytic activity can also be expected. However, when the content of P ₂ O ₅ exceeds 50%, the above-described photocatalytic crystal phase is difficult to precipitate. Therefore, the upper limit of the content of the P ₂ O ₅ component with respect to the total amount of glass or glass ceramics in terms of oxide is preferably 50%, more preferably 45%, and most preferably 40%. Further, P ₂ O ₅ case of containing the component is preferably 1% or more the effect as an amount capable of sufficiently exhibited, and more preferably 5% or more, most preferably be 10% or more. The P ₂ O ₅ component is made of, for example, glass using Al (PO ₃ ) ₃ , Ca (PO ₃ ) ₂ , Ba (PO ₃ ) ₂ , Na (PO ₃ ), BPO ₄ , H ₃ PO ₄ or the like as a raw material. It can be introduced into glass ceramics.

The B ₂ O ₃ component is a component that constitutes a glass network structure and improves the stability of the glass, and can be optionally added. However, if the content exceeds 50%, the chemical durability of the glass is lowered, and the tendency of the desired photocatalytic crystals to be difficult to precipitate when heated to precipitate crystals increases. Therefore, the content of the B ₂ O ₃ component is preferably 50%, more preferably 40%, and most preferably 30% with respect to the total amount of glass or glass ceramics in oxide equivalent composition. The B ₂ O ₃ component can be introduced into glass or glass ceramics using, for example, H ₃ BO ₃ , Na ₂ B ₄ O ₇ , Na ₂ B ₄ O ₇ .10H ₂ O, BPO ₄ or the like as a raw material. .

The SiO ₂ component is a component that constitutes the glass network structure and improves the stability and chemical durability of the glass, and the component that contributes to the improvement of the photocatalytic activity by dissolving Si ⁴⁺ ions in the NASICON crystal. Yes, a component that can be optionally added. However, when the content of the SiO ₂ component exceeds 50%, the meltability of the glass is deteriorated and the desired photocatalytic crystal phase is hardly precipitated. Therefore, the content of the SiO ₂ component with respect to the total amount of glass or glass ceramics in terms of oxide is preferably 1%, more preferably 3%, most preferably 5% as the lower limit, preferably 50%, more preferably Has an upper limit of 40%. SiO ₂ component can be introduced into the glass or the glass ceramics is used as a raw material such as _{SiO 2, K 2 SiF 6,} Na 2 SiF 6 or the like.

The GeO ₂ component is a component having a function similar to that of the above-described SiO ₂ and can be arbitrarily added to the glass ceramic. In particular, by setting the content of the GeO ₂ component to 50% or less, use of an expensive GeO ₂ component can be suppressed, so that the material cost of glass or glass ceramics can be reduced. Therefore, the content of GeO ₂ component to glass or glass-ceramic total substance amount of oxide basis composition, preferably 50%, more preferably 40% GeO ₂ component and most preferably up to 30%, as a raw material For example, it can be introduced into glass or glass ceramics using GeO ₂ or the like.

Li 2 _O component improves the meltability and stability of glass is a component which constitutes the NASICON type crystal is a component that can be added optionally. However, if the content of the Li ₂ O component exceeds 35%, the stability of the glass is deteriorated, and precipitation of TiO ₂ crystals, NASICON crystals, WO ₃ crystals, ZnO crystals, etc. becomes difficult. Therefore, the Li ₂ O component content is preferably 35%, more preferably 30%, and most preferably 25% with respect to the total amount of glass or glass ceramics having an oxide equivalent composition. However, when trying to precipitate a NASICON type crystal containing Li ⁺ ions, the Li ₂ O component is essential, and its content is preferably 0.5% or more, more preferably 1% or more, and most preferably Is in the range of 2% or more. Incidentally, Li ₂ O component may be introduced into the glass or the glass ceramics, for example, using _Li 2 _CO 3 as a raw material, LiNO _3, LiF and the like.

Na 2 _O component improves the meltability and stability of glass is a component which constitutes the NASICON type crystal is a component that can be added optionally. However, if the content of the Na ₂ O component exceeds 35%, the stability of the glass is deteriorated, and precipitation of TiO ₂ crystals, NASICON crystals, WO ₃ crystals, ZnO crystals, etc. becomes difficult. Therefore, the upper limit of the content of the Na ₂ O component is preferably 35%, more preferably 30%, and most preferably 25% with respect to the total amount of glass or glass ceramics having an oxide equivalent composition. However, when trying to precipitate Nasicon-type crystals containing Na ⁺ ions, the Na ₂ O component is essential, and its content is preferably 0.5% or more, more preferably 1% or more, and most preferably Is in the range of 2% or more. Incidentally, Na ₂ O component may be introduced into the glass or the glass ceramic used as raw materials for example _{Na 2 O, Na 2 CO 3} , NaNO 3, NaF, Na 2 S, the Na 2 SiF ₆ or the like.

K 2 _O component improves the meltability and stability of glass is a component which constitutes the NASICON type crystal is a component that can be added optionally. However, when the content of the K ₂ O component exceeds 35%, the stability of the glass is deteriorated, and precipitation of TiO ₂ crystals, NASICON crystals, WO ₃ crystals, ZnO crystals and the like becomes difficult. Therefore, the upper limit of the content of the K ₂ O component with respect to the total amount of glass or glass ceramic material in oxide equivalent composition is preferably 35%, more preferably 30%, and most preferably 25%. However, when a Nasicon-type crystal containing K ⁺ ions is to be precipitated, the K ₂ O component is essential, and its content is preferably 0.5% or more, more preferably 1% or more, and most preferably Is in the range of 2% or more. Incidentally, _{K 2} O ingredients may be introduced into the glass or the glass ceramics by using the raw material as for example _{K 2 CO 3, KNO 3,} KF, KHF 2, K 2 SiF 6 and the like.

Glass or glass ceramics may contain 40% or less of at least one component selected from Rn ₂ O (wherein Rn is one or more selected from the group consisting of Li, Na, and K). preferable. In particular, when the total amount of the Rn ₂ O component is 35% or less, the stability of the glass is improved and a desired crystal phase is easily precipitated, so that the catalytic activity of the glass ceramic can be ensured. Therefore, the total amount of the Rn ₂ O component is preferably 35%, more preferably 30%, and most preferably 25% with respect to the total amount of glass or glass ceramics having an oxide equivalent composition. Moreover, when trying to precipitate a NASICON type crystal phase containing Rn ⁺ ions, the total amount of Rn ₂ O component is preferably 0.5%, more preferably 1% in order to obtain good photocatalytic activity. Most preferably, the lower limit is 2%.

The MgO component is a component that improves the meltability and stability of glass and constitutes a NASICON crystal, and can be optionally added. However, if the content of the MgO component exceeds 40%, the stability of the glass is worsened, and precipitation of TiO ₂ crystals, NASICON crystals, WO ₃ crystals, ZnO crystals, etc. becomes difficult. Therefore, the upper limit of the content of the MgO component with respect to the total amount of glass or glass ceramics having an oxide equivalent composition is preferably 40%, more preferably 35%, and most preferably 30%. However, when a NASICON crystal containing Mg ²⁺ ions is to be deposited, the content is preferably 1% or more, more preferably 2% or more, and most preferably 3% or more. Incidentally, MgO component can be introduced into the glass or the glass ceramics used as the starting material for example MgCO _3, MgF ₂ or the like.

The CaO component is a component that improves the meltability and stability of glass and constitutes a NASICON crystal, and can be optionally added. However, if the content of the CaO component exceeds 40%, the stability of the glass is deteriorated, and precipitation of TiO ₂ crystals, NASICON crystals, WO ₃ crystals, ZnO crystals and the like becomes difficult. Therefore, the upper limit of the CaO component content is preferably 40%, more preferably 35%, and most preferably 30% with respect to the total amount of glass or glass ceramics having an oxide equivalent composition. However, when a NASICON type crystal containing Ca ²⁺ ions is to be precipitated, the content is preferably 1% or more, more preferably 2% or more, and most preferably 3% or more. Incidentally, CaO component can be introduced into the glass or the glass ceramics used as the starting material for example CaCO _3, CaF ₂ and the like.

The SrO component is a component that improves the meltability and stability of the glass and constitutes a NASICON crystal, and can be optionally added. However, if the content of the SrO component exceeds 40%, the stability of the glass is worsened, and precipitation of TiO ₂ crystals, NASICON crystals, WO ₃ crystals, ZnO crystals, etc. becomes difficult. Therefore, the upper limit of the SrO component content is preferably 40%, more preferably 35%, and most preferably 30% with respect to the total amount of glass or glass ceramics having an oxide equivalent composition. However, when a Nasicon type crystal containing Sr ²⁺ ions is to be precipitated, the SrO component is essential, and its content is preferably 1% or more, more preferably 2% or more, and most preferably 3% or more. And Incidentally, SrO component as a raw material for example with _{Sr (NO 3) 2, SrF} 2 , etc. can be introduced into the glass or the glass ceramics.

The BaO component is a component that improves the meltability and stability of the glass and constitutes a NASICON crystal, and can be optionally added. However, if the content of the BaO component exceeds 40%, the stability of the glass is worsened, and precipitation of TiO ₂ crystals, NASICON crystals, WO ₃ crystals, ZnO crystals, etc. becomes difficult. Therefore, the upper limit of the BaO component content is preferably 40%, more preferably 35%, and most preferably 30% with respect to the total amount of glass or glass ceramics having an oxide equivalent composition. However, when a Nasicon type crystal containing Ba ²⁺ ions is to be precipitated, the BaO component is essential, and its content is preferably 1% or more, more preferably 2% or more, and most preferably 3% or more. And Incidentally, BaO component as a raw material for example BaCO _{3, Ba (NO 3)} with 2, BaF ₂ and the like can be introduced into the glass or the glass ceramics.

Glass or glass ceramics preferably contains 40% or less of at least one component selected from RO (wherein R is one or more selected from the group consisting of Mg, Ca, Sr and Ba). . In particular, when the total amount of RO components is 40% or less, the stability of the glass is improved, and a crystal phase such as a TiO ₂ crystal, a WO ₃ crystal, a ZnO crystal, and a NASICON type crystal phase are easily precipitated. The catalytic activity of glass ceramics can be ensured. Therefore, the total amount of the RO component is preferably 40%, more preferably 35%, and most preferably 30% with respect to the total amount of glass or glass ceramics in oxide equivalent composition. In addition, when a NASICON type crystal phase containing R ²⁺ ions is to be precipitated, the total amount of RO components is preferably 1%, more preferably 2%, most preferably in order to obtain good photocatalytic activity. 3% is the lower limit.

Further, glass or glass ceramic is composed of Rn ₂ O (wherein Rn is one or more selected from the group consisting of Li, Na, and K) and RO (wherein R is Mg, Ca, Sr, and Ba). It is preferable to contain 40% or less of at least one component selected from one or more components selected from the group consisting of: In particular, by making the total amount of the Rn ₂ O component and the RO component 40% or less, the stability of the glass is improved, and TiO ₂ crystal, NASICON type crystal, WO ₃ crystal, ZnO crystal and the like are easily precipitated. Glass ceramics excellent in photocatalytic activity can be obtained more easily. On the other hand, when the total amount of the Rn ₂ O component and the RO component is more than 40%, the stability of the glass is deteriorated, and precipitation of a crystal phase such as a TiO ₂ crystal, a WO ₃ crystal, a ZnO crystal, or a NASICON crystal phase. It will also be difficult. Accordingly, the total amount (Rn ₂ O + RO) with respect to the total amount of glass or glass ceramics in terms of oxide composition is preferably 40%, more preferably 35%, and most preferably 30%. When these components are included, the lower limit is preferably 0.1%, more preferably 0.5%, and most preferably 1% in order to obtain the effect.

Here, the glass or glass ceramic is composed of Rn ₂ O (wherein Rn is one or more selected from the group consisting of Li, Na, K, Rb and Cs) and an RO (wherein R is Be, Mg). By containing two or more components selected from the group consisting of one or more selected from the group consisting of Ca, Sr and Ba, the stability of the glass is greatly improved, and the glass ceramics machine after heat treatment The strength becomes higher, and a crystal phase such as a TiO ₂ crystal, a WO ₃ crystal, or a ZnO crystal, or a NASICON type crystal phase is more likely to precipitate from glass. Therefore, glass or glass ceramic preferably contains two or more of the components selected from Rn 2 _O component and the RO component.

Fe ₂ O ₃ component is a component that enhances the stability of glass and the chemical durability of glass ceramics and promotes precipitation of NASICON crystals from glass. Is an ingredient that can be added arbitrarily. However, when the content exceeds 10%, vitrification becomes difficult. Therefore, the upper limit of the content of the Fe ₂ O ₃ component with respect to the total amount of the glass or glass ceramic material in oxide equivalent composition is preferably 10%, more preferably 5%, and most preferably 3%. On the other hand, when the Fe ₂ O ₃ component is added, the lower limit is preferably 0.0001%, more preferably 0.002%, and most preferably 0.005% in order to express the effect of the component. The Fe ₂ O ₃ component can be introduced into glass or glass ceramics using, for example, Fe ₂ O ₃ or Fe ₂ O ₄ as a raw material.

The SnO component is a component that constitutes a NASICON crystal, promotes precipitation of the NASICON crystal, and has an effect of improving the photocatalytic properties by dissolving in the NASICON crystal. In addition, when added together with Au or Pt ions, which will be described later, which has the effect of enhancing the photocatalytic activity, it is a component that contributes indirectly to the improvement of the photocatalytic activity by acting as a reducing agent, and can be arbitrarily added. It is an ingredient. However, if the content of these components exceeds 10%, the stability of the glass is deteriorated, and the photocatalytic properties are liable to deteriorate. Therefore, the total content of the SnO component with respect to the total amount of glass or glass ceramic material in oxide equivalent composition is preferably 10%, more preferably 8%, and most preferably 5%. Further, when the SnO component is added, the lower limit is preferably 0.01%, more preferably 0.02%, and most preferably 0.03%. SnO components can be introduced into the glass or glass ceramic used as the starting material for example _SnO, SnO 2, SnO ₃ and the like.

The ZrO ₂ component is a component that can be added arbitrarily as it constitutes a nasicon type crystal, enhances the chemical durability of the glass ceramics, and provides a photocatalytic activity by constituting the nasicon type crystal. However, when the content of the ZrO ₂ component exceeds 20%, vitrification becomes difficult. Therefore, the upper limit of the content of the ZrO ₂ component with respect to the total amount of glass or glass ceramics in terms of oxide is 20%, preferably 10%, more preferably 8%, and most preferably 5%. Further, when adding the ZrO ₂ component, the lower limit is preferably 0.5%, more preferably 1%, and most preferably 2%. ZrO ₂ component can be introduced into the glass or glass ceramic is used as a raw material such as _ZrO 2, ZrF _4, and the like.

The HfO ₂ component has an effect of providing photocatalytic activity by constituting a NASICON crystal, and can be optionally added. However, when the content of the HfO ₂ component exceeds 40%, vitrification becomes difficult. Therefore, the upper limit of the content of the HfO ₂ component with respect to the total amount of glass or glass ceramics in oxide equivalent composition is, for example, 40%, preferably 10%, more preferably 5%, and most preferably 3%. Further, when the HfO ₂ component is added, the lower limit is preferably 0.01%, more preferably 0.03%, and most preferably 0.1%. The HfO ₂ component can be introduced into glass or glass ceramics using, for example, HfO ₂ as a raw material.

The V ₂ O ₅ component is a component that has an effect of providing photocatalytic activity by constituting a NASICON crystal and can be arbitrarily added. Moreover, there exists an effect which brings about photocatalytic activity by comprising a NASICON type crystal | crystallization itself. However, when the content of the V ₂ O ₅ component exceeds 10%, vitrification becomes difficult. Therefore, the content of the V ₂ O ₅ component is preferably 10%, more preferably 5%, and most preferably 3% with respect to the total amount of glass or glass ceramics in terms of oxide. _Also, when adding V 2 _{O 5} component, in order to express the effect, preferably 0.0001%, more preferably 0.002%, and most preferably the lower limit 0.005%. The V ₂ O ₅ component can be introduced into glass or glass ceramics using, for example, V ₂ O ₅ as a raw material.

Nb ₂ O ₅ component is a component which enhances the meltability and stability of glass and is a component that can be added optionally. Moreover, there exists an effect which brings about photocatalytic activity by comprising a NASICON type crystal | crystallization itself. However, when the content of the Nb ₂ O ₅ component exceeds 30%, the stability of the glass is remarkably deteriorated. Therefore, the upper limit of the content of the Nb ₂ O ₅ component with respect to the total amount of glass or glass ceramics in terms of oxide is preferably 30%, more preferably 20%, and most preferably 15%. The Nb ₂ O ₅ component can be introduced into glass or glass ceramics using, for example, Nb ₂ O ₅ as a raw material.

The Ta ₂ O ₅ component is a component that enhances the stability of the glass and can be optionally added. Moreover, there exists an effect which brings about photocatalytic activity by comprising a NASICON type crystal | crystallization itself. However, when the content of the Ta ₂ O ₅ component exceeds 30%, the stability of the glass is remarkably deteriorated. Therefore, the upper limit of the content of the Ta ₂ O ₅ component with respect to the total amount of glass or glass ceramics in oxide equivalent composition is, for example, 30%, preferably 20%, more preferably 15%, and most preferably 10%. The Ta ₂ O ₅ component can be introduced into glass or glass ceramics using, for example, Ta ₂ O ₅ as a raw material.

The MoO ₃ component is a component that improves the meltability and stability of the glass, and can be optionally added. Moreover, there exists an effect which brings about photocatalytic activity by comprising a NASICON type crystal | crystallization itself. However, when the content of the MoO ₃ component exceeds 30%, the stability of the glass is remarkably deteriorated. Therefore, the upper limit of the content of the MoO ₃ component with respect to the total amount of glass or glass ceramics in terms of oxide is preferably 30%, more preferably 20%, and most preferably 10%. The MoO ₃ component can be introduced into glass or glass ceramics using, for example, MoO ₃ as a raw material.

The Al ₂ O ₃ component is a component that improves the stability of the glass and the chemical durability of the glass ceramic, and contributes to the improvement of the photocatalytic activity by the solid solution of Al ³⁺ ions in the TiO ₂ crystal and NASICON crystal phase. , A component that can be optionally added. However, when the content exceeds 30%, the melting temperature is remarkably increased and vitrification becomes difficult. Therefore, when the Al ₂ O ₃ component is added, the content of the Al ₂ O ₃ component with respect to the total amount of glass or glass ceramic of the oxide conversion composition is preferably 0.1%, more preferably 0.5%, Most preferably, 1% is the lower limit, preferably 30%, more preferably 20%, and most preferably 15%. The Al ₂ O ₃ component can be introduced into glass or glass ceramics using, for example, Al ₂ O ₃ , Al (OH) ₃ , AlF ₃ or the like as a raw material.

The Ga ₂ O ₃ component is a component that enhances the stability of the glass and contributes to the improvement of the photocatalytic activity by solid solution of Ga ³⁺ ions in the TiO ₂ crystal and NASICON type crystal phase, and can be optionally added. . However, when the content exceeds 30%, the melting temperature is remarkably increased and vitrification becomes difficult. Therefore, the upper limit of the content of the Ga ₂ O ₃ component is preferably 30%, more preferably 15%, and most preferably 10% with respect to the total amount of glass or glass ceramics having an oxide equivalent composition. Ga ₂ O ₃ component can be introduced into the glass or glass ceramic used as the raw material for instance _Ga 2 _{O 3,} GaF 3, and the like.

The In ₂ O ₃ component is a component having an effect similar to that of the above Al ₂ O ₃ and Ga ₂ O ₃ and can be arbitrarily added. Since the In ₂ O ₃ component is expensive, the upper limit of its content with respect to the total amount of glass or glass ceramics having an oxide conversion composition is preferably 10% or less, more preferably 8% or less. % Or less is most preferable. The In ₂ O ₃ component can be introduced into glass or glass ceramics using, for example, In ₂ O ₃ , InF ₃ or the like as a raw material.

The Bi ₂ O ₃ component is a component that improves the meltability and stability of the glass, is a component that further dissolves in the photocatalytic crystal and improves the photocatalytic activity, and can be optionally added. However, when the content of the Bi ₂ O ₃ component exceeds 20%, the stability of the glass is remarkably deteriorated. Therefore, the upper limit of the content of the Bi ₂ O ₃ component with respect to the total amount of glass or glass ceramics in terms of oxide is preferably 20%, more preferably 15%, and most preferably 10%. On the other hand, when the TiO ₂ crystal is precipitated from the glass ceramic, if the ratio of the Bi ₂ O ₃ component to the TiO ₂ component (Bi ₂ O ₃ / TiO ₂ ) is 0.12 or more, the stability of the glass deteriorates, Precipitation of TiO ₂ becomes difficult. Therefore, when TiO ₂ crystals are precipitated from glass ceramics, the ratio (Bi ₂ O ₃ / TiO ₂ ) is preferably less than 0.12, more preferably 0.06 or less, and 0 0.03 or less is most preferable. The Bi ₂ O ₃ component can be introduced into glass or glass ceramics using, for example, Bi ₂ O ₃ as a raw material.

The TeO ₂ component is a component that improves the meltability and stability of the glass, is a component that further dissolves in the photocatalytic crystal and improves the photocatalytic activity, and can be optionally added. However, when the content of the TeO ₂ component exceeds 20%, the stability of the glass is remarkably deteriorated. Therefore, the content of the TeO ₂ component is preferably 20%, more preferably 15%, and most preferably 10% with respect to the total amount of glass or glass ceramics in oxide equivalent composition. The TeO ₂ component can be introduced into glass or glass ceramics using, for example, TeO ₂ as a raw material.

Ln ₂ O ₃ component (wherein Ln is selected from the group consisting of Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) Is a component that enhances the chemical durability of the glass ceramic, and is a component that improves the photocatalytic activity by being dissolved in the crystal phase of the photocatalyst or existing in the vicinity thereof. , A component that can be optionally added. However, if the total content of the Ln ₂ O ₃ components exceeds 30%, the stability of the glass is significantly deteriorated. Therefore, the total amount of the Ln ₂ O ₃ component is preferably 30%, more preferably 10%, and most preferably 5% with respect to the total amount of glass or glass ceramic material in oxide equivalent composition. The Ln ₂ O ₃ component includes, for example, La ₂ O ₃ , La (NO ₃ ) ₃ .XH ₂ O (X is an arbitrary integer), Gd ₂ O ₃ , GdF ₃ , Y ₂ O ₃ , YF ₃ , CeO as raw materials. ₂ , CeF ₃ , Nd ₂ O ₃ , Dy ₂ O ₃ , Yb ₂ O ₃ , Lu ₂ O _3, etc., can be introduced into glass or glass ceramics.

M _x O _y component (wherein M is at least one selected from the group consisting of Cr, Mn, Co, and Ni, and x and y are minimums satisfying x: y = 2: M valence, respectively) Where the valence of Cr is 3, the valence of Mn is 1, the valence of Co is 2, and the valence of Ni is 2.) is dissolved in the crystalline phase of the photocatalyst? Or a component that contributes to the improvement of the photocatalytic activity by being present in the vicinity thereof and absorbs visible light having a certain wavelength to impart an appearance color to the glass ceramic, and is an optional component. In particular, when the total amount of the M _x O _y components is 10% or less, the stability of the glass ceramic can be improved and the appearance color can be easily adjusted. Therefore, the total amount of the M _x O _y component is preferably 10%, more preferably 5%, and most preferably 3% with respect to the total amount of glass or glass ceramic material in oxide equivalent composition. When these components are added, the lower limit is preferably 0.0001%, more preferably 0.002%, and most preferably 0.005%. The M _x O _y component can be introduced into glass or glass ceramics using, for example, Cr ₂ O ₃ .

As ₂ O ₃ component and / or Sb ₂ O ₃ component is a component for clarifying and defoaming glass, and when added together with Ag, Au, and Pt ions, which will be described later, and has the effect of enhancing photocatalytic activity. Since it plays the role of a reducing agent, it is a component that indirectly contributes to the improvement of the photocatalytic activity and can be optionally added. However, when the content of these components exceeds 5% in total, the stability of the glass is deteriorated, and the photocatalytic activity is easily lowered. Therefore, the total content of the As ₂ O ₃ component and / or the Sb ₂ O ₃ component with respect to the total amount of glass or glass ceramics in terms of oxide composition is preferably 5%, more preferably 3%, most preferably 1. % Is the upper limit. When these components are added, the lower limit is preferably 0.001%, more preferably 0.002%, and most preferably 0.005%. As ₂ O ₃ component and Sb ₂ O ₃ component are, for example, As ₂ O ₃ , As ₂ O ₅ , Sb ₂ O ₃ , Sb ₂ O ₅ , Na ₂ H ₂ Sb ₂ O ₇ .5H ₂ O and the like as raw materials. And can be introduced into glass or glass ceramics.

The components for clarifying and defoaming the glass are not limited to the above As ₂ O ₃ component and Sb ₂ O ₃ component. For example, such as CeO ₂ component, TeO ₂ component, etc. Well-known fining agents and defoaming agents in the field, or a combination thereof can be used.

The glass or glass ceramic used in the present embodiment includes one or more non-metallic element components selected from the group consisting of F component, Cl component, Br component, S component, N component, and C component. Also good. These components are components that improve the photocatalytic activity by being dissolved in the crystal phase of the photocatalyst or existing in the vicinity thereof, and can be optionally added. However, when the content of these components exceeds 20% in total, the stability of the glass is remarkably deteriorated, and the photocatalytic activity is likely to be lowered. Therefore, in order to ensure good characteristics, the total of the externally divided mass ratio of the content of the nonmetallic element component to the total mass of the glass or glass ceramic of the oxide conversion composition is preferably 20%, more preferably 10%, Most preferably, the upper limit is 5%. These nonmetallic element components are preferably introduced into glass or glass ceramics in the form of fluorides, chlorides, bromides, sulfides, nitrides, carbides or the like of alkali metals or alkaline earth metals. In addition, the content of the nonmetallic element component in this specification is assumed to be made of oxides in which all of the cation components constituting the glass or glass ceramic are combined with oxygen that can balance the charge. The total mass of non-metallic element components extracted separately and expressed as mass%, with the total mass of the glass or glass ceramic as 100% (external mass% with respect to the oxide-based mass). The raw material of the non-metallic element component is not particularly limited. For example, ZrF ₄ , AlF ₃ , NaF, CaF _{2 and the} like are used as the raw material for the F component, NaCl and AgCl are used as the raw material for the Cl component, NaBr is used as the raw material for the Br component, S Introducing into glass ceramics by using NaS, Fe ₂ S ₃ , CaS _2, etc. as ingredient raw materials, AlN ₃ , SiN ₄ etc. as N ingredient raw materials, TiC, SiC or ZrC etc. as C ingredient raw materials Can do. These raw materials may be added in combination of two or more, or may be added alone.

The glass or glass ceramic used in the present embodiment contains at least one metal element component selected from a Cu component, an Ag component, an Au component, a Pd component, a Ru component, a Rh component, a Re component, and a Pt component. May be. These metal element components are components that improve photocatalytic activity by being present in the vicinity of the photocatalytic crystal phase, and can be optionally added. Among these, in particular, the Cu component and the Ag component constitute a NASICON type crystal and have the effect of bringing about photocatalytic activity in the same manner as the alkali and alkaline earth components described above. By containing these components, further irradiation with light is possible. It is possible to develop high antibacterial properties even if there is no. However, if the total content of these metal element components exceeds 10%, the stability of the glass is remarkably deteriorated, and the photocatalytic activity tends to decrease. Accordingly, the total content of the above metal element components with respect to the total mass of the glass or glass ceramic of the oxide conversion composition is preferably 10%, more preferably 5%, and most preferably 3%. These metal element components are made of, for example, glass using CuO, Cu ₂ O, Ag ₂ O, AuCl ₃ , PtCl ₂ , PtCl ₄ , H ₂ PtCl ₆ , RuO ₂ , RhCl ₃ , ReCl ₃ , PdCl ₂ or the like as raw materials. Or it can introduce | transduce into glass ceramics. In addition, the content of the metal element component in the present specification is expressed as an externally divided mass% with respect to the oxide-based mass. When these components are added, the lower limit is preferably 0.001%, more preferably 0.002%, and most preferably 0.005%.

  Components other than the above components can be added to the glass or glass ceramics as necessary within a range not impairing the properties of the glass ceramics. However, lead compounds such as PbO, each component of Th, Cd, Tl, Os, Be, Se, and Hg tend to refrain from being used as harmful chemical substances in recent years, not only in the manufacturing process of glass or glass ceramics, Environmental measures are required until processing and disposal after commercialization. Therefore, when importance is placed on the environmental impact, it is preferable not to substantially contain them except for inevitable mixing. As a result, substances that pollute the environment are not substantially contained in glass or glass ceramics, and the photocatalyst member of the present invention can be manufactured, processed, and disposed of without taking any special environmental measures. it can.

  The form of the glass or glass ceramic is not particularly limited, and may be, for example, a granular shape (including granules), a plate shape, a porous body, or the like. Here, when using a granular material as glass or glass ceramics, it is preferable to use one having a particle diameter of 0.5 μm or more from the viewpoint of precipitating inorganic crystals to be described later and obtaining high photocatalytic activity.

[Photocatalytic crystal]
The photocatalytic crystal that can be precipitated from the glass, the photocatalytic crystal contained in the glass ceramic, or the photocatalytic crystal as the photocatalytic material is not particularly limited as long as it has photocatalytic activity. TiO ₂ crystal, WO ₃ crystal, RnNbO ₃ crystal, RnTaO ₃ crystal (where Rn is one or more selected from Li, Na and K), RNb ₂ O ₆ crystal, RTa ₂ O ₆ crystal (here , R means one or more selected from Be, Mg, Ca, Sr, Ba and Zn), Bi ₂ WO ₆ crystal, Bi ₂ W ₂ O ₉ crystal, SrTiO ₃ crystal, ZnO crystal, and the like It is preferable to include one or more kinds of crystals selected from the solid solution. Hereinafter, typical ones will be described.

<NASICON type crystal>
The NASICON crystal can be represented by the general formula A _m E ₂ (XO ₄ ) ₃ . Since the compound represented by the general formula A _m E ₂ (XO ₄ ) ₃ stably has a NASICON structure, high photocatalytic activity can be obtained. Here, it is preferable that the element A is, for example, one or more selected from the group consisting of Li, Na, K, Cu, Ag, Mg, Ca, Sr, Ba, and Zn. Since the ions of element A are present at the site forming a three-dimensional tunnel in the crystal, these ions move easily inside the crystal, and the probability of recombination of electrons and holes caused by light irradiation is reduced. As a result, the photocatalytic activity of the NASICON crystal is improved. Element A is, for example, Li ₂ CO ₃ , LiNO ₃ , LiF, Na ₂ O, Na ₂ CO ₃ , NaNO ₃ , NaF, Na ₂ S, Na ₂ SiF ₆ , K ₂ CO ₃ , KNO ₃ , KF, _{KHF 2, K 2 SiF 6,} CuO, Cu 2 O, CuCl, Ag 2 O, AgCl, MgCO 3, MgF 2, CaCO 3, CaF 2, Sr (NO 3) 2, SrF 2, BaCO 3, Ba (NO ₃ ) ₂ , BaF ₂ , ZnO, ZnF ₂ or the like can be introduced into the glass ceramic.

The element E is preferably one or more selected from the group consisting of, for example, Zn, Al, Fe, Ti, Sn, Zr, Ge, Hf, V, Nb, and Ta. However, A and E are different components. These are components necessary for forming a stable NASICON-type crystal structure, and are components that form a band gap in the range of 2.5 to 4 eV by being involved in the formation of the conduction band. Therefore, it is possible to obtain not only ultraviolet light but also visible light responsive photocatalytic activity by containing any of the above elements. Further, from the viewpoint of improving the photocatalytic activity, it is more preferable that the element E contains Ti, Zr, Fe or the like, and it is most preferable that Ti is contained. The element E is a raw material such as ZnO, ZnF ₂ , Al ₂ O ₃ , Al (OH) ₃ , AlF ₃ , FeO, Fe ₂ O ₃ , TiO ₂ , SnO, SnO ₂ , SnO ₃ , ZrO ₂ , ZrF ₄ , GeO ₂ , Hf ₂ O ₃ , V ₂ O ₅ , Nb ₂ O ₅ , Ta ₂ O _5, etc. can be used for introduction into the glass ceramic.

Moreover, it is preferable that the element X contains the 1 type (s) or 2 or more types chosen, for example from Si, P, S, Mo, and W. These elements are components necessary for forming a stable NASICON crystal structure, and have an effect of adjusting the size of the band gap of the NASICON crystal. The element X preferably contains Si, P, S, W, etc., and most preferably contains P, from the viewpoint of facilitating formation of a NASICON crystal. Element X is SiO ₂ , K ₂ SiF ₆ , Na ₂ SiF ₆ , Al (PO ₃ ) ₃ , Ca (PO ₃ ) ₂ , Ba (PO ₃ ) ₂ , Na (PO ₃ ), BPO ₄ , H ₃ PO ₄ , NaS, Fe ₂ S ₃ , CaS ₂ , WO ₃ , MoO ₃ or the like can be used to introduce into glass ceramics.

M in the general formula A _m E ₂ (XO ₄ ) ₃ is selected according to the type of E or X, but is a number in the range of 0 or more and 5 or less. When m is in this range, the NASICON crystal structure is maintained, and the thermal and chemical stability is enhanced. In addition, the degradation of the photocatalytic activity due to environmental changes is reduced, and the photocatalytic activity is not easily lowered by heating. On the other hand, if m exceeds 5, the NASICON structure cannot be maintained, and the photocatalytic activity decreases.

Specific examples of NASICON crystals include RnTi ₂ (PO ₄ ) ₃ , R _0.5 Ti ₂ (PO ₄ ) ₃ , RnZr ₂ (PO ₄ ) ₃ , R _0.5 Zr ₂ (PO ₄ ) ₃ , RnGe ₂ (PO ₄ ) ₃ , R _0.5 Ge ₂ (PO ₄ ) ₃ , Rn ₄ AlZn (PO ₄ ) ₃ , Rn ₃ TiZn (PO ₄ ) ₃ , Rn ₃ V ₂ (PO ₄ ) ₃ , Al _{0. 3} Zr ₂ (PO ₄ ) ₃ , Rn ₃ Fe (PO ₄ ) ₃ , RnNbAl (PO ₄ ) ₃ , La _1/3 Zr ₂ (PO ₄ ) ₃ , Fe ₂ (MoO ₄ ) ₃ , Fe ₂ (SO ₄₎ ) ₃ , Rn ₄ Sn ₂ (SiO ₄ ) ₃ , Rn ₄ Zr ₂ (SiO ₄ ) ₃ , Cu ₄ Zr ₂ (SiO ₄ ) ₃ , Ag ₄ Zr ₂ (SiO ₄ ) ₃ , R ₂ Zr ₂ (SiO ₄₎ ) _3, NbTi (PO _{4 3, RnZr 2 (Si 2/3 P} 1/3 O 4) 3, RTiCr (PO 4) 3, RTiFe (PO 4) 3, RTiIn (PO 4) 3, ZnTiFe (PO 4) 3 ( wherein, Rn Is at least one selected from the group consisting of Li, Na, K, Rb and Cs, and R is at least one selected from the group consisting of Be, Mg, Ca, Sr and Ba). Can do. Furthermore, among Nasicon type crystals, alkali metal titanium phosphate complex salts such as NaTi ₂ (PO ₄ ) ₃ , LiTi ₂ (PO ₄ ) ₃ , KTi ₂ (PO ₄ ) ₃ , and Ca _0.5 Ti ₂ (PO ₄ ). ₃ , crystals of alkaline earth metal titanium phosphate complex such as Mg _0.5 Ti ₂ (PO ₄ ) _3, Sr _0.5 Ti ₂ (PO ₄ ) ₃ , Ba _0.5 Ti ₂ (PO ₄ ) ₃ More preferably. By containing these NASICON crystals, photocatalytic activity is improved, and mechanical strength and chemical durability are greatly improved.

The NASICON crystal structure forms a three-dimensional network structure by connecting the EO ₆ octahedron and the XO ₄ tetrahedron so as to share a vertex. In this three-dimensional network structure, there are two sites where A ions can exist, and these two sites form a continuous three-dimensional tunnel, so that the A ions easily move in the crystal. be able to. With such a structure, it is considered that the probability of recombination of electrons and holes caused by light irradiation is reduced, and it is possible to stably exhibit excellent photocatalytic activity. In addition, NASICON crystals have the advantage that they are thermally stable without phase transition, and the photocatalytic activity is not easily lost by heating conditions such as baking.

<TiO ₂ crystal, WO ₃ crystal, ZnO crystal>
The TiO ₂ crystal exhibits strong photocatalytic activity in an ultraviolet region having a wavelength of 400 nm or less, and particularly preferably contains an anatase type or rutile type TiO ₂ crystal. Since the WO ₃ crystal absorbs visible light up to a wavelength of 480 nm and exhibits photocatalytic activity, it imparts visible light responsive photocatalytic activity to the photocatalytic member. The ZnO crystal has a band gap of about 3 to 4 eV, and brings photocatalytic activity to the photocatalytic member in the same manner as the TiO ₂ crystal.

  Further, the crystallization rate of the glass ceramic used as a raw material in the method for producing the photocatalyst member of the present embodiment is preferably 90% or less, more preferably 85% or less in volume ratio. The more the glass phase is in the glass ceramic, the easier it is for the protruding inorganic crystals to be described later to precipitate, and the photocatalytic activity of the photocatalytic member tends to increase.

  The photocatalytic crystal preferably exhibits catalytic activity by light having a wavelength from the ultraviolet region to the visible region. Here, the light having a wavelength in the ultraviolet region is an invisible electromagnetic wave having a wavelength shorter than that of visible light and longer than that of soft X-ray, and the wavelength thereof is in a range of approximately 10 nm to 400 nm. The light having a wavelength in the visible region is an electromagnetic wave having a wavelength that can be seen by human eyes among electromagnetic waves, and the wavelength is in a range of approximately 400 nm to 780 nm. When the photocatalyst member is irradiated with light having any wavelength from the ultraviolet region to the visible region, or light having a composite wavelength of these, the hydrophilicity is imparted or soiled. And organic substances such as bacteria are decomposed by oxidation or reduction reaction.

[Hydrothermal treatment]
Hydrothermal treatment can be performed, for example, by using a heat-resistant / pressure-resistant vessel such as an autoclave, placing a raw material and a solution such as water therein, and placing the autoclave in a heating device such as an electric furnace and heating. The treatment temperature of the hydrothermal treatment is, for example, 100 to 450 ° C. from the viewpoint of efficiently generating and growing photocatalytic crystals in the photocatalytic member produced by hydrothermal treatment and promoting precipitation of inorganic crystals on the surface of the photocatalytic member. Within the range, the range of 110 to 440 ° C. is more preferable.

  The treatment time of the hydrothermal treatment step is, for example, in the range of 1 to 720 hours from the viewpoint of sufficiently growing the photocatalytic crystal in the photocatalytic member produced by the hydrothermal treatment and precipitating inorganic crystals on the surface of the photocatalytic member. The inside is preferable, and the inside of the range of 2 to 710 hours is more preferable.

  Hydrothermal treatment can be performed in addition to water, for example, in an alkaline aqueous solution, an acidic aqueous solution, or a mixed solution thereof. Examples of the alkaline aqueous solution include a sodium hydroxide aqueous solution, a potassium hydroxide aqueous solution, a calcium hydroxide aqueous solution, ammonia water, a sodium carbonate aqueous solution, and a sodium hydrogen carbonate aqueous solution. Examples of the acidic aqueous solution include a hydrofluoric acid aqueous solution, hydrochloric acid, sulfuric acid, nitric acid, carbonic acid, acetic acid, and citric acid. By using an alkaline aqueous solution or an acidic aqueous solution, effects such as precipitation of zeolite on the photocatalyst member and enhancement of the photocatalytic activity by etching the glass surface can be expected. On the other hand, by performing hydrothermal treatment with water, manufacturing cost and environmental load can be reduced.

  As described above, the method for producing a photocatalyst member of the present embodiment can produce a photocatalyst member having high photocatalytic activity from a photocatalyst material by a simple process by utilizing hydrothermal treatment. Therefore, a photocatalyst member having excellent photocatalytic activity and useful as a photocatalytic functional material can be easily produced on an industrial scale without using special equipment. Moreover, the photocatalyst member obtained by the method of the present invention has a high degree of freedom in processing the size and shape, and can be used for various applications that require a photocatalytic function.

[Photocatalyst member]
A preferable aspect of the photocatalyst member of the present embodiment manufactured as described above is a photocatalyst member provided with glass or glass ceramics containing a crystal phase having photocatalytic activity, and has a projection-like inorganic crystal on the surface. Is precipitated. Here, the inorganic crystals are precipitated by hydrothermal treatment of glass or glass ceramic as a raw material. The material of the projecting inorganic crystal is not yet clear, but it is presumed to be, for example, a certain photocatalytic crystal or a solid solution thereof, or a crystal of an adsorbing substance such as zeolite. As the reason, in the photocatalyst member of the present embodiment, it is confirmed that the photocatalytic activity is enhanced as shown in the examples described later by precipitation of protruding inorganic crystals. Moreover, in the photocatalyst member of the present embodiment, it is confirmed that the amount of cesium adsorbed increases as shown in the examples described later, due to precipitation of protruding inorganic crystals. When the protruding inorganic crystal is an adsorbing substance such as zeolite, the organic substance is adsorbed by its adsorption action, so that the chance of contact with the photocatalytic crystal of the photocatalytic member increases, and the photocatalytic activity is indirectly increased. It is thought that there is.

  The shape of the inorganic crystal may be various shapes such as a spherical shape, a long spherical shape, a bowl shape, a cubic shape, a polyhedron, a plate shape, and a scale shape. The inorganic crystal preferably has an average crystal diameter measured by a scanning electron microscope in the range of 0.05 μm to 500 μm. When the average diameter of the inorganic crystals is less than 0.05 μm, the photocatalytic activity or the enhancing effect thereof may be insufficient. When the average diameter exceeds 500 μm, the crystals may peel from the photocatalytic member.

  The photocatalyst member produced as described above can be used as a functional material having a photocatalytic action as it is or after being processed into an arbitrary shape. That is, the photocatalyst member of the present embodiment can be used, for example, as a water purification material, a gas purification material, or a hydrophilic member (for example, a window, a mirror, a panel, a tile, or the like). Further, since the photocatalytic member of the present embodiment has a cesium adsorption performance, it can be used for the purpose of decontamination of radioactive substances such as radioactive cesium and radioactive strontium. In addition, the photocatalyst member of this Embodiment does not ask | require the shape, such as a bulk state and a powder form, for example.

  EXAMPLES Next, although an Example is given and this invention is demonstrated in more detail, this invention is not restrict | limited at all by the following Examples. In addition, the various measurement in an Example was performed with the following method.

[Methylene blue decomposition ability evaluation]
A 0.02 mM methylene blue aqueous solution (hereinafter referred to as “adsorption solution”) and a 0.01 mM methylene blue aqueous solution (hereinafter referred to as “test solution”) were prepared. Then, the sample was put into a resin container having an inner diameter of 20 mm, a width of 86 mm, and a height of 45 mm, and 3 ml of the adsorbing solution was poured, and the adsorbing solution was sufficiently adsorbed on the sample for 24 hours while preventing light from being applied. . Next, with respect to the adsorbed liquid after adsorption, the absorbance with respect to light having a wavelength of 664 nm is measured using a spectrophotometer (manufactured by JASCO Corporation, model number: V-650). Adsorption was completed when the absorbance was greater than the measured absorbance. Next, after replacing the liquid in the container with the same amount of the test liquid as the adsorbed liquid, 1.0 mW / cm ² of ultraviolet light was irradiated, and the absorbance to light having a wavelength of 664 nm was measured. The absorbance at each time was compared with the initial one, and the ratio was used to evaluate the decomposition ability of methylene blue.

[Cs adsorption power evaluation]
CsCl aqueous solution (manufactured by Rare Metal Co., Ltd .: cesium chloride) prepared with pure water and the sample are placed in a resin container with an inner diameter of 20 mm, a width of 86 mm, and a height of 45 mm and sealed at 100 rpm without using a ball in a ball mill. Stir for 24 hours. Subsequently, only the solution was taken out by filtration, and the cesium concentration was measured with an ICP-OES multi-emission spectroscopic analyzer (manufactured by Agilent Technologies, Inc .: ICP-OES · 720-ES).

[Acetaldehyde decomposition power evaluation]
The sample was placed in a 500 ml capacity quartz chamber (Makuhari Chemical Chemical Industries, Ltd., top irradiation cell type II-S) with gas inlets and outlets on two sides, and a quartz lid was applied. The lid and the chamber were brought into close contact with silicon grease. One of the gas inlets and outlets of the chamber is connected to a gas outlet of a photoacoustic dual gas monitor (manufactured by LumaSense Technologies: 1412-2 INNOVA photoacoustic dual gas monitor), and the other is a 1 L capacity aluminum bag (GL) with two gas inlets and outlets. Science Co., Ltd .: CCK type). The other gas inlet / outlet of the aluminum bag was connected to the gas inlet / outlet of the photoacoustic dual gas monitor using a Teflon (registered trademark) tube, a silicon tube, or a SUS fitting. Next, pure air (G2 air, manufactured by Taiyo Nippon Sanso Corporation) with a humidity of 50% was poured into the chamber from the tube to replace the air in the chamber. Thereafter, 15 ml of 1% acetaldehyde gas (manufactured by Sumitomo Seika Co., Ltd., N ₂ balance) is taken into a gas tight syringe, injected into the chamber from the tube, and acetaldehyde gas is applied for 30 minutes while avoiding exposure to light. After making it adsorb | suck to a sample, the ultraviolet ray of 1.0 mW / cm < ² > was irradiated.

[Synthesis example]
Production of raw glass:
As raw materials for each component, high-purity raw materials used for ordinary glass such as corresponding oxides, hydroxides, carbonates, nitrates, chlorides, and metaphosphate compounds were selected. These raw materials were weighed so as to have the ratios of composition A and composition B shown in Table 1 and mixed uniformly, and then put into a platinum crucible, which was 1200 to 1650 ° C. depending on the difficulty of melting the glass composition. It melt | dissolved in the temperature range for 1 to 24 hours, and homogenized with stirring, and foaming etc. were performed. Thereafter, the temperature was lowered to 1500 ° C. or lower, and the mixture was stirred and homogenized, and then the molten glass was poured into water and water-crushed to produce a raw glass.

[Examples 1-9, Comparative Examples 1-7]
The photocatalyst member was obtained by heat-processing with respect to the raw material glass manufactured as mentioned above on the conditions shown in Table 2 or Table 3, and also implementing the hydrothermal treatment to the glass ceramic obtained by heat processing. The heat treatment shown in Table 2 or Table 3 was performed in an electric furnace with granular glass placed in a platinum crucible and plate-shaped glass placed on a refractory. The etching treatment shown in Table 2 or Table 3 was performed with 46 wt% hydrofluoric acid (manufactured by Wako Pure Chemical Industries, Ltd., special grade) after heat treatment and before hydrothermal treatment. The hydrothermal treatment shown in Table 2 or Table 3 is put in a 100 ml autoclave (Pressure Glass Industry Co., Ltd .: Portable Reactor TVS-1-100 ml) together with 15 ml of pure water, sealed, and then left in an electric furnace. went.

  The image (magnification 5000 times) which image | photographed the surface of the photocatalyst member obtained in Example 1 with the scanning electron microscope (SEM) was shown in FIG. From FIG. 1, inorganic crystals generated by hydrothermal treatment were confirmed on the surface of the photocatalytic member of Example 1. Similarly, the SEM image (5000 times magnification) of the surface of the photocatalyst member obtained in Example 2 is shown in FIG. 2, and the SEM image (500 times magnification) of the surface of the photocatalyst member obtained in Example 3 is shown in FIG. The SEM images (500 times magnification) of the surface of the photocatalyst member obtained in Example 7 are shown in FIG. 2 to 4, inorganic crystals of various shapes generated by hydrothermal treatment were confirmed on the surface of the photocatalyst member obtained in each example.

[Test Example 1]
The photocatalytic member obtained in Example 1, the glass obtained in Comparative Example 1, and the glass ceramic obtained in Comparative Example 2 were evaluated for methylene blue decomposition ability. The results are shown in FIG. From FIG. 5, in Example 1 which performed hydrothermal treatment, the improvement of the methylene blue decomposition ability was confirmed clearly compared with the glass ceramics (comparative example 2) with the same raw material composition and shape. In addition, methylene blue decomposition ability was not able to be confirmed in the glass (comparative example 1) with the same raw material composition and shape as Example 1.

[Test Example 2]
As in Test Example 1, the photocatalyst member obtained in Examples 4 to 6, the glass obtained in Comparative Example 3, the glass ceramics obtained in Comparative Example 4 and Comparative Example 5 were irradiated with ultraviolet rays and non-irradiated (dark) And methylene blue decomposition ability was evaluated. The results are shown in FIG. From FIG. 6, it was confirmed that the photocatalytic members obtained in Examples 4 to 6 were decomposed by methylene blue only during irradiation with ultraviolet rays and exhibited photocatalytic activity. Moreover, it was confirmed from the comparison with Example 4 and Example 5 that photocatalytic activity improves, so that the time of hydrothermal treatment is long. Furthermore, from comparison between Example 4 and Example 6, it was confirmed that excellent photocatalytic activity could be obtained even with a short hydrothermal treatment depending on the raw material composition.

[Test Example 3]
For the photocatalyst members obtained in Example 5 and Example 8, the glass ceramics obtained in Comparative Example 4 and Comparative Example 6, Cs adsorption force evaluation was performed using the sample amounts shown in Table 4. The results are shown in FIGS. 7 and 8, it was confirmed that the amount of adsorbed cesium was clearly increased in Examples 5 and 8 where hydrothermal treatment was performed as compared with the state of glass ceramics. 9 and 10, it was confirmed that the amount of adsorbed cesium increased in proportion to the amount of sample in Examples 5 and 8 where hydrothermal treatment was performed.

[Test Example 4]
Next, the acetaldehyde decomposition ability evaluation was implemented about the photocatalyst member obtained in Example 9, and the glass ceramic obtained in Comparative Example 7. The results are shown in FIG. From FIG. 11, it was confirmed that the photocatalyst member obtained in Example 9 was developed to decompose acetaldehyde only during irradiation with ultraviolet rays, and exhibited photocatalytic activity.

  From the above results, it was confirmed that the photocatalytic member obtained by hydrothermal synthesis of the raw glass ceramics had improved photocatalytic activity compared to the glass ceramics.

As mentioned above, although embodiment of this invention was described in detail for the purpose of illustration, this invention is not restrict | limited to the said embodiment, A various deformation | transformation is possible.

Claims (17)

  A method for producing a photocatalyst member, comprising a step of hydrothermally treating a photocatalyst material.   The method for producing a photocatalyst member according to claim 1, wherein a treatment temperature in the hydrothermal treatment step is in a range of 100 to 450 ° C.   The method for producing a photocatalytic member according to claim 1, wherein a treatment time of the hydrothermal treatment step is within a range of 1 to 720 hours.   The method for producing a photocatalytic member according to any one of claims 1 to 3, wherein the hydrothermal treatment is performed in at least one solvent selected from the group consisting of water, an alkaline aqueous solution, and an acidic aqueous solution.   The method for producing a photocatalytic member according to any one of claims 1 to 4, wherein the photocatalytic material is glass or glass ceramics.   The method for producing a photocatalyst member according to claim 5, wherein the glass has a composition capable of precipitating crystals having photocatalytic activity by heat treatment.   The method for producing a photocatalytic member according to claim 5, wherein the glass ceramic has crystals having photocatalytic activity. The glass or glass ceramic is in mol% based on the total amount of the oxide-converted composition,
(1) At least one selected from the group consisting of P ₂ O ₅ component, B ₂ O ₃ component, SiO ₂ component, and GeO ₂ component is in the range of 1 to 90%;
(2) Rn ₂ O component (where Rn means one or more selected from Li, Na, K), RO component (where R is one or more selected from Mg, Ca, Sr, Ba) Cu ₂ O component, Ag ₂ O component, ZnO component, Al ₂ O ₃ component, Fe ₂ O ₃ component, TiO ₂ component, SnO component, ZrO ₂ component, HfO ₂ component, V ₂ O ₅ component 1 or more components selected from Nb ₂ O ₅ component, Ta ₂ O ₅ component, MoO ₃ component and WO ₃ component in the range of 0.0001 to 99%;
The manufacturing method of the photocatalyst member of Claim 6 or 7 respectively contained by. The crystals having photocatalytic activity are NASICON type crystals, TiO ₂ crystals, WO ₃ crystals, RnNbO ₃ crystals, RnTaO ₃ crystals (where Rn is one or more selected from Li, Na and K), RNb ₂ 1 selected from O ₆ crystal, RTa ₂ O ₆ crystal (where R means one or more selected from Be, Mg, Ca, Sr, Ba and Zn), ZnO crystal, and solid solutions thereof The method for producing a photocatalyst member according to any one of claims 6 to 8, wherein the photocatalyst member is a seed or more crystal. The NASICON-type crystal is a general formula A _m E ₂ (XO ₄ ) ₃ (wherein A is selected from the group consisting of Li, Na, K, Cu, Ag, Mg, Ca, Sr, Ba, and Zn 1 Means E or more, E means one or more selected from the group consisting of Zn, Al, Fe, Ti, Sn, Zr, Ge, Hf, V, Nb and Ta, and X means Si, P, S, The photocatalyst according to claim 9, which represents one or more selected from the group consisting of Mo and W, wherein the coefficient m is 0 or more and 5 or less, and A and E are different components. Manufacturing method of member.   The method for producing a photocatalytic member according to any one of claims 1 to 10, wherein the glass or glass ceramic is powdery or plate-like. The method for producing a photocatalyst member according to claim 1, wherein the glass or glass ceramic is a porous body. A photocatalyst member comprising glass or glass ceramics containing a crystal phase having photocatalytic activity, wherein a projecting inorganic crystal is deposited on a surface.   The photocatalytic member according to claim 13, wherein the inorganic crystal has an average crystal diameter measured by a scanning electron microscope in a range of 0.05 μm to 500 μm.   The photocatalyst member according to claim 13 or 14, wherein the inorganic crystal is precipitated by subjecting glass or glass ceramic as a raw material to hydrothermal treatment. The crystals having photocatalytic activity are NASICON type crystals, TiO ₂ crystals, WO ₃ crystals, RnNbO ₃ crystals, RnTaO ₃ crystals (where Rn is one or more selected from Li, Na and K), RNb ₂ 1 selected from O ₆ crystal, RTa ₂ O ₆ crystal (where R means one or more selected from Be, Mg, Ca, Sr, Ba and Zn), ZnO crystal, and solid solutions thereof The photocatalyst member according to claim 13, wherein the photocatalyst member is a seed or more crystal. The NASICON-type crystal is a general formula A _m E ₂ (XO ₄ ) ₃ (wherein A is selected from the group consisting of Li, Na, K, Cu, Ag, Mg, Ca, Sr, Ba, and Zn 1 Means E or more, E means one or more selected from the group consisting of Zn, Al, Fe, Ti, Sn, Zr, Ge, Hf, V, Nb and Ta, and X means Si, P, S , Mo and W means one or more selected from the group consisting of, and the coefficient m is 0 or more and 5 or less, and A and E are different components. Photocatalyst member.